s investigation last year of tamerlan tsarnaev, after he spent six months in russia. senator diane feinstein, chairing the intelligence committee, said senior f.b.i. may testify tomorrow about why they did not pursue the matter further. i misspoke in that set-up piece. tsarnaev was read his miranda rights in his hospital room today. we're joined by a reporter who has been following developments closely. dina temple raston is npr as anti-terrorism correspondent. welcome to you. do we know how much or what investigators are learning from tsarnaev in the hospital so far? >> well, there's been very little that they've learnd because he can't really understand that he can't speak. he has a tube in his throat. he has some sort of a wound on his neck and his hand. apparently to his jaw. there's some question as to whether or not it was a self-inflicted wound. so as a result apparently they're writing notes back and forth. it's unclear if those notes are ra port building so he learns to trust these people who are trying to question him or where they're getting substantive inf